Marceline's Step Sister
by BlueAndBlackAngel
Summary: Oh yeah! It's Marceline's birthday. Well almost any way. When her step-sister Alex comes to her for help, Marceline takes her in but after Marceline's place was ransacked, she kicks Alex out! Can Marceline, Finn, and Jake find her step-sister before she causes even more trouble? FinnXOC


**Hello FF! I really love AT so I just had to make a FF! Alex is my OC! Read and review or this is the only chapter of the story.**

The moon shined proudly in the sky as two adventurers made their way to Marceline's house. Her birthday was at midnight, and they wanted to take her to the beach, since she couldn't go in the daytime. Everyone had already RSVP'd for her party that was going to happen tomorrow night. Finn was determined to make this her best birthday ever. I mean, come on! How many times does a vampire turn 1,234 years old?

"I'm so pumped, man," Finn wiggled his arms and grinned, "I'm so pumped that I could do a flip!" He ran forward and did flipped, causing him to land on his back,

Jake ran over and helped him up, "Yeah, man. This party is going to be huge!" Jake started to stretch and Finn jumped on his back. Jake grew taller than the treetops and the two could see all of Ooo. Marceline's house was barely visible in the distance.

Finn stared up at the stars. He was so excited to go swimming with the beach especially with Marceline. Finn frowned slightly. She was 1,234 years old, well 1,233 years old anyways, and he was only 13. The age difference itself should stop him from crushing on her. She had already said she didn't like him _like _that, but his heart was head over heels for her.

Getting uncomfortable with the silence that left him to his thoughts, Finn spoke up, "Hey, Jake. Drop me a beat!" Finn's companion started beat boxing.

He cleared his voice and began to make up a song on how totally righteous their night was going to be.

**XxXxXxXxX**

When they arrived at Marceline's, Jake shrunk back down to size and Finn jumped off his back. Jake went to the door and pushed it forward without knocking.

"Jake! You can't just walk into her house!" Finn yelled, but still followed after him. Screaming flooded over Finn and Jake as they entered the room.

There Marceline stood in a flow-y tan top and a pair of jean shorts with her boots. A bag was dropped be hand her but over all her room was bare. She towered in the air over a girl curled up into a small ball. The girl had on combat boots and black hair with blue tips.

Since Marceline hadn't seen or heard Finn and Jake enter, she continue to scream, "Are you so weak that you couldn't have taken who ever stole my stuff?"

The girl with blue tips hugged her knees and whispered, "I'm…I'm not weak. I just…"

"You just what, Alex? Why didn't you do something?" Marceline floated higher as her anger rose. Her hair whipped around her and her eyes were red with pure red. She went on, "They took everything! I hate you, Alex!"

Alex flinched and looked like she was trying to bury head in her knees. It looked like she just wanted to disappear altogether. She mumbled something and then spoke a little louder, "I'm…sorry…Marcy…I-I-I…didn't think-"

Turning her back to the girl, Marceline picked up her bag, "Whatever, Alex. Go back to the Nightosphere! You are not welcomed here!"

"Oh, but Marcy!" Alex's face shot up and she looked like she had been stabbed in the heart and broken to pieces. If she weren't so sad, Finn would have taken her as beautiful. "I can't go back there! Marceline, Please!"

Marceline turned back to answer her, but she saw Finn and Jake standing there. "Guys! Ever heard of knocking?" Finn and Jake just stood there awkwardly. From intruding into their friend's home and Marceline's yelling.

"Hello? Guys?" Marceline floated over, completely calm, "Are we still hitting the beach?"

Finn switched from foot to foot, "Um yeah. I just didn't know you had a friend tagging along." He began walking over to Alex, "Hi, I'm-,"

Before he could step any closer, Marceline grabbed him by the collar of his shirt, "She is not tagging along and she is more of a nuisance. Besides, Alex was just leaving," Marceline shot a glare in Alex's direction.

Slowly and solemnly, Alex stood and floated off the ground. "It is nice to know my step-sister really loves me," She spat and came over toward the boys and Marceline. She looked into her step-sister's wild angry eyes and reflected the same feelings towards her. "Happy early birthday," Alex took something out of her boot and threw it on the floor in front of Marceline's feet. It was an envelope.

"Come on, Ruffles." A rat scurried over from the spot Alex had been sitting, up her arm and onto her shoulder. She floated from the room and slammed the door.

Jake spoke up, "Whoa, someone stole your stuff? That's got to suck!"

Marceline shrugged, "I let that dimwit watch my house for a couple our and this happens." An aching hate throbbed in Marceline's head.

She never liked Alex. She was just so irritating and couldn't do anything right. Even though she had constantly tried to be helpful to Marceline, Alex always ended up ruining something.

The only reason Alex had come to Marceline was because her dad, and Alex's step-dad, wanted to her to take control over the Nightosphere. He wanted to be able to just relax with his wife. Marceline's dad didn't even know that Alex had run away yet.

"Why were you so mean to your little sister? It isn't her fault. Maybe she couldn't take them." Finn didn't know the girl but she surely didn't deserve the wrath of Marceline. No one did.

Boiling anger surged inside Marceline as she growled, "She is not my sister! We are not related! Can we please just go to the beach now?" Without waiting for a reply, Marceline opened the door and slammed it behind her. She was sure that this was going to be the worst birthday ever.

**Hey guys! Did you like it? If you did let me know in a review! Thanks!**


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